Simple Question: What does Power armor made for normal humands look like?

Sororitas minus boobplate, essentially. Or like this guy .

Cool pic Errant. Very Roman looking.

The heavy power armor picture in the Into the Storm book looks pretty Sphase Mharines-ish.

My suggestion regarding Civilian power armor. The people who could afford a set are the high and mighty so can probably afford to have them customized to suit their personal tastes and style since. After all it's not required to conform to any sort of military standards in general appearance or color. So to me it seems that you've got a lot of wiggle room to take artistic license and say it looks however you like. Heck one piece might very well be modified enough or encrusted with bling enough that it will look entirely different from another PA of the same mark and weight class.

So go crazy.

Are you Iron Man? Cool. Might actually be a bit boring for 40k. Maybe it's a new suit and hasn't had a chance to be dolled up yet.

Steam punk up your armor with lots of tubes and baroque filigree? Nice. Maybe it's particularly old or on the alternative often repaired with some sub-standard stuff.

Do you look like a Gwar extra in armor? Suit must have belonged to a pretty brutal dude at some point who added spikey tooths and bolts and stuff.

Are you a walking fire hazard covered in wax seals tacking on strips of paper scripture? Must have been a religious guy. Better leave it be or you could draw the Emprah's displeasure.

In my head, most "standard" Imperium-made power armour, as far as that word can be used regarding power armour,

is going to resemble Astartes Power Armour in some respect, quite simply due to most of them being based on Astartes-patterns, but scaled down. There is, however, going to be custom-made armours resembling all kinds of things like Spatulaodoom noted above. Then there's armours made in the Expanse, who aren't tech-heresy per se, simply made in a different design than most Imperial armours. So go wild, but do remember that they're usually a bit more practical than their Astartes predecessors, so there'll probably be less silly pauldrons.

Also, for references, see this I found: http://31.media.tumblr.com/9502ceca812333e1dfcb3dc3b708a31e/tumblr_ml61quW9By1r21rsxo1_500.jpg

Also check out Inquisitor Drogan from Warhammer 40k: Space Marine, who has an Inquisition-made power armour.

I'm not even talking about custom made, but armor that's had junk added to it after it was built.

Do take care regarding the size of your shoulder pads though. It's like the C-church and their hats. Your rank and status is supposed to be reflected by the size and number of your shoulder pads. If you show up at a party with mini-refrigerators on your shoulders while your boss only has 5 gallon pails you're gonna be in trouble. Little known fact but way back in the day Power Armor was originally intended to function as a pauldron support system, increasing the size of pauldron the human body could support.

Because Rogue Traders fall outside all the normal rules they can't do that, so they decided to do the same thing amongst one another with hats.